What is multihoming was (design of a real routing v. endpoint id seperation)

Tue Oct 25 12:56:29 UTC 2005

> From owner-nanog at merit.edu  Mon Oct 24 15:33:02 2005
> Date: Mon, 24 Oct 2005 13:31:17 -0700
> Subject: Re: What is multihoming was (design of a real routing v. endpoint id
>  seperation)
>
> Stephen Sprunk wrote:
> [snip]
>
> >> Other people use this term in very different ways. To some people
> >> it means using having multiple IP addresses bound to a single
> >> network interface. To others it means multiple websites on one
> >> server.
> > 
> > 
> > That is virtual hosting in a NANOG context.  Some undereducated MCSEs 
> > might call it multihoming, but let's not endorse that here.
>
> Unfortunately, this is a common and "standards blessed" way to refer to
> any host with multiple interfaces/addresses (real or virtual). For example,
> from the "Terminology" section, 1.1.3, of RFC1122, "Requirements for
> Internet Hosts -- Communication Layers," says,
>
>           Multihomed
>                A host is said to be multihomed if it has multiple IP
>                addresses.  For a discussion of multihoming, see Section
>                3.3.4 below.
>

*sigh*  Multi-homing simply means 'having external connections to more than 
one network' -- be it a network with multiple, disjoint, ingress/egress paths,
or a host with interfaces (real or virtual) on distinct LAN subnets (even if
those subnets are agregated into a single net somewhere upstream.

A host with multiple adresses utilizing the _same_ netblock/netmask _should_
_not_ be called multi-homed (because there is only one path to that host), it
is simply a single-homed host with multiple identities.  might be called
"poly-ip-any" or some such.  <grin>